Frequent Ozone Depletion Resulting from Impacts of Asteroids and Comets

Abstract

The fossil record reveals that the evolution of life on Earth has been punctuated by a number of catastrophic events, of which one of the most devastating occurred at the end of the Cretaceous, approximately 66 million years ago. The postulate introduced in 1980 by Alvarez et al. (1980) that the collision of an approximately 10 km diameter asteroid with the Earth caused the extinction of the dinosaurs along with more than half of all plant and animal species has resulted in a greatly expanded research efforts in the area of catastrophic events (Alvarez et al. 1980).